Plant Biology and Cell Basics Flashcards

Vocabulary flashcards covering cellular biology basics, cell theory, membrane transport, and plant anatomy and physiology.

Lipids

Fats/oils used for energy storage, cell membrane structure (phospholipids), and insulation.

Carbohydrates

Sugars/starches/cellulose provide quick energy and structural support (cell walls).

Proteins

Amino acid chains involved in muscle, enzymes, transport, regulation, and defense.

Enzymes

Catalytic proteins that speed up chemical reactions without being consumed.

Antibodies

Immune proteins that neutralize pathogens/diseases.

Open Systems

Systems that exchange both matter and energy with their surroundings.

Closed Systems

Systems that exchange energy only, not matter.

Isolated Systems

Systems that exchange neither matter nor energy.

3 Postulates of Cell Theory

All living organisms are composed of one or more cells. The cell is the basic functional unit of life. All cells come from pre-existing cells.

Hooke

Scientist who coined the term "cell" after observing cork under a simple microscope.

Leeuwenhoek

First scientist to observe living moving cells ("animalcules") under a microscope.

Schleiden & Schwann

Proposed that all plants (Schleiden) and all animals (Schwann) are made of cells.

Pasteur

Disproved "spontaneous generation" using swan-neck flasks, proving cells only come from existing cells.

Cell Membrane

A phospholipid bilayer that acts as a semi-permeable barrier controlling cell entry/exit.

Cytoplasm

Jelly-like fluid that holds organelles and serves as the site of metabolic reactions.

Nucleus

The control center of the cell that houses DNA and chromosomes.

Mitochondria

The site of cellular respiration where glucose is converted into $\text{ATP}$ energy.

Ribosomes

Sites of protein synthesis that are either free-floating or attached to the Rough ER.

Endoplasmic Reticulum (ER)

Rough ER has ribosomes for processing proteins; Smooth ER lacks ribosomes and makes lipids and detoxifies.

Golgi Apparatus

The cell's packaging center that modifies and ships proteins and lipids in vesicles.

Vacuoles

Storage units for water and waste; animals have many small ones, while plants have one large central vacuole.

Cell Wall (Plants)

Rigid cellulose layer outside the membrane providing support and protection.

Chloroplasts (Plants)

Photosynthesis site containing chlorophyll to convert light $\rightarrow$ glucose.

Large Central Vacuole (Plants)

Huge water storage organelle that maintains turgor pressure for plant rigidity.

Lysosomes (Animals)

Organelles containing digestive enzymes to break down waste and old organelles.

Centrioles (Animals)

Organelles that organize cell division (mitosis).

Fluid Mosaic Model

A flexible lipid layer embedded with floating proteins describing the membrane structure.

Phospholipid Bilayer

Composed of hydrophilic heads (water-loving, face out) and hydrophobic tails (fatty acid, face in).

Glycolipid

A lipid with a sugar chain attached, used for cell stability, tissue formation, and signaling.

Glycoprotein

A protein with a sugar chain attached, used for cell recognition and hormone reception.

Transport Proteins

Include Channel proteins (open pore for fast passage) and Carrier proteins (bind molecule and change shape).

Receptor Proteins

Proteins that bind external signals like hormones to trigger internal cellular responses.

Recognition Proteins

Molecular "ID tags" used for immune identification of self vs. foreign entities.

Passive Transport

Movement from High $\rightarrow$ Low concentration without the need for $\text{ATP}$ energy.

Diffusion

Passive movement of small or non-polar molecules directly through the phospholipid bilayer.

Osmosis

The passive diffusion of water across a semi-permeable membrane.

Facilitated Diffusion

Passive transport of substances using specific channel or carrier proteins.

Active Transport

Movement from Low $\rightarrow$ High concentration (against gradient) requiring $\text{ATP}$.

Protein Pumps

Membrane proteins that use $\text{ATP}$ to force molecules against their concentration gradient.

Endocytosis

Active transport process where the membrane engulfs large materials into vesicles.

Exocytosis

Active transport process where vesicles fuse with the membrane to dump waste or proteins out.

Dermal Tissue (Epidermis)

Outer protective 1-cell layer and regulator of gas/water exchange.

Cuticle

Waxy, non-living layer on the epidermis that prevents water loss.

Ground Tissue

Middle tissue layer used for storage, structural support, and the main site of photosynthesis.

Palisade Mesophyll

Upper ground layer of tightly packed column cells filled with chloroplasts for photosynthesis.

Spongy Mesophyll

Lower ground layer with loose air spaces for gas diffusion of $\text{CO}_2$, $\text{O}_2$, and $\text{H}_2\text{O}$.

Vascular Tissue

Internal transport system of tubes for distributing water, minerals, and sugars.

Xylem

Hollow, dead cells that transport water and minerals upward from the roots.

Phloem

Living cells that transport sugars (sucrose) both up and down from the leaves.

Phloem Cells

Consist of Sieve-Tubes (conducting cells with no nucleus) and Companion Cells (supply energy and support).

Meristems

Plant growth tissue featuring active mitosis areas for increasing length and width.

Root Hairs

Epidermal extensions that increase root surface area to maximize water absorption.

Stomata & Guard Cells

Stomata are leaf pores for gas exchange, flanked by Guard Cells that control their opening and closing.

Guard Cells OPENING

Active pump $\text{K}^+$ IN $\rightarrow$ Water follows by osmosis $\rightarrow$ Cells swell (turgid) $\rightarrow$ Stoma opens.

Guard Cells CLOSING

$\text{K}^+$ diffuses OUT $\rightarrow$ Water leaves by osmosis $\rightarrow$ Cells go limp (flaccid) $\rightarrow$ Stoma closes.

Transpiration Pull

Evaporation of water from leaves creates suction that pulls the xylem water column upward.

Cohesion vs. Adhesion

Cohesion refers to water sticking to water; Adhesion refers to water sticking to xylem walls.

Root Pressure

Minerals pumped into roots $\rightarrow$ Water follows by osmosis $\rightarrow$ Upward push from the bottom.

Phototropism

Growth response to light; stems show positive response (toward) and roots show negative (away).

Gravitropism

Growth response to gravity; stems show negative response (up) and roots show positive (down).

Auxin Mechanism

Hormone moves to the shaded side of the stem $\rightarrow$ elongates shaded cells $\rightarrow$ bends stem toward light.